Q. There was something almost comforting in the old idea that after all the outracing galaxies emanating from the Big Bang 15 billion years ago finally "run out of gas," they'd come gravitationally falling back in together toward a Big Crunch– maybe to be followed by Big Bang II or III... The universe i like a big accordion. But you can scratch that idea, say cosmologists today. Instead, where are all the galaxies racing toward, including our own Milky Way? –C. Sagan

A. We're riding a pointless explosion to nowhere, never to run out of gas, never to return, as writer John Updike put it. Rather the galaxies seem to be expanding at an accelerating rate, though no one can say "where" they're headed since space itself is expanding, says Massachusetts Institute of Technology physicist Scott Hughes. From the point of view of us in the Milky Way, all the other galaxies are racing away from us while we sit still; to alien astronomers in another galaxy, all the other galaxies are racing away from them– a little like spots on a balloon growing more distant from each other as the balloon is inflated.

Are there exceptions? Yes, says Hughes: if two galaxies are close enough, their gravitational interaction can overwhelm space expansion, such as our Milky Way galaxy and the Andromeda galaxy racing toward a spectacular collision with each other, probably in a few billion years.

But whether that beats racing to nowhere is hard to say.

Q. It's the largest organ of the body, a little over 20 pounds for a 150-pound person. It fends off microbes and functions as a body thermostat as its blood vessels constrict or dilate. A single square centimeter contains some 200 nerve endings, 100 sweat glands, 15 oil glands, 10 hairs, 2 cold receptors and 25 pressure-sensing receptors. What's this busy body part? –S. Burton

Q. Can anybody guess the product when 111,111,111 is multiplied by 111,111,111? –C.VanDoren

A. 12,345,678,987,654,321

Q. Extreme summer heat raises the question: "Are greenhouse gases such as carbon dioxide in Earth's atmosphere a good or a bad thing?" Basically, greenhouse gases slow the escape of heat from a planet's surface, causing it to warm up.–A. Gore

A. This is not the same as asking "Is global warming a good or a bad thing?" Some greenhouse gases are present naturally in the atmosphere, and with them, the global average temperature is about 59 degrees F, say Jeffrey Bennett and William Briggs in Using and Understanding Mathematics: A Quantitative Reasoning Approach. That's the temperature of a deep cave. Without these gases, the global temperature would be closer to a frigid 0 degrees F. "Thus the greenhouse effect is a good thing for life on Earth," the authors write.

But it has been shown that carbon dioxide is increasing in concentration in the atmosphere. And on Venus, a runaway greenhouse effect has sent temperatures soaring (global warming) to around 870 degrees F, "demonstrating that even for planets it's possible to have too much of a good thing."

Q. It's called "the Fermi paradox," and the deeper humankind looks into it, the more profound its implications become. As Arthur C. Clarke once pointed out, the question must have an answer, one way or other, and either way, it will be equally amazing. In fact, if we ever learn the answer, it will cause the most dramatic shift in the status of our human species that has ever occurred in history. What is this famous question? –A. C. Clarke

A. Nobel-prize winning physicist Enrico Fermi posed this during a 1950 discussion with other scientists about extraterrestrial intelligence: If alien civilizations really are as common as it seems they ought to be, "Where is everybody?" Partly the answer to this means thinking about what a grown-up civilization might do, says Jeffrey Bennett in Beyond UFOs. Though we've never yet met one, Bennett explains, I have a pretty good idea what we humans must do to become one: We must grow and grow in wisdom because only if we learn to find solutions to worldly problems such as global warming, poverty, disease, terrorism and war– and only if we do all of this together– can we stay around long enough to gain the necessary knowledge and technology to reach outward to embrace "what lies beyond." If we can do this, "the possibilities that await us are infinite."

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Send strange questions to brothers Bill and Rich at strangetrue@compuserve.com.